The treatment of mental illness during pregnancy has gained considerable attention over the past decade. The majority of this attention has focused on antidepressants and major depression, with far less consideration of anxiety disorders and bipolar disorder. The treatment guidelines for mental illness during pregnancy and lactation remain empiric and continue to emphasize the risk/benefit assessment. The lack of data on the course of illness, the impact of pregnancy and lactation of the metabolism and distribution of pharmacological treatments, and the extent of fetal and neonatal medication exposure underscores the empiric nature and prematurity of such guidelines. The current project will enhance and extend the data derived from an ongoing collaborative R01 MH56555-01A2 (Stowe) focused on the relapse of major depression in pregnant women taking antidepressant proximate to conception and K23 MH 63507-01 (Newport) investigating psychosis during pregnancy. We will prospectively follow women with major depression (MID), bipolar disorder (BPD), panic disorder (PD), and obsessive-compulsive disorder (OCD) through pregnancy and the first postpartum year. Many of these women may chose to continue medications such as antidepressants, mood stabilizers, and antipsychotic medications either during pregnancy and/or take medications postpartum. Monthly serum sampling and GCRC admissions will provide novel data.regarding the metabolism, distribution, and fetal/neonatal exposure to these compounds. These PK/PD models will be expanded to include assessment of pharmacogenetic factors of metabolic capacity and protein binding. Similarly, prospective documentation of additional exposures, sex steroid concentrations, and psychosocial variables will further refine such models and provide preliminary assessment of factors (other than medication concentrations) that may influence the course of illness and obstetrical outcome. The current project will utilize the core components to address the deficits in the current literature, affords a diagnostically diverse group of women that may be germane to the results obtained in Project 2 with respect to co-morbidity and the use of similar medications in a non-epileptic population.